Elastic bag for aerial delivery



July 11, 1961 P. o. PFEIFFER 2,991,815

ELASTIC BAG FOR AERIAL DELIVERY Original Filed Dec. 17, 1951 2Sheets-Sheet 1 F 5 INVENTOR 7' Paul 0. Pf'eif'fer ATTORNEYS y 1961 P. o.PFEIFFER 2,991,815

ELASTIC BAG FOR AERIAL DELIVERY Original Filed Dec. 17, 1951 2Sheets-Sheet 2 INVENTOR Paul 0- Pleifler BY Cam 0% ATTORNEYS UnitedStates Patent 2,991,815 ELASTIC BAG FOR AERIAL DELIVERY Paul 0.Pfeifier, Akron, Ohio, assignor to The General Tfirg Rubber Company,Akron, Ohio, a corporation 0 0 Application Aug. '30, 1956, Ser. No.607,185, which is a continuation of application Ser. No. 262,116, Dec.17, 1951. Divided and this application Aug. 1, 195"], Ser. No. 675,981

9 Claims. (Cl. 150-1) The present invention relates to an article ofmanufacture. Specifically, it relates to a strong, flexible, elastic bagwhich may be filled with flowable material and dropped to the ground.

This application is a division of my copending application, Serial No.607,185, filed August 30, 1956, which is a continuation of myapplication, Serial No. 262,116, filled December 17, 1951, nowabandoned.

A most pressing military supply problem is to supply isolated pocketsand units of men with provisions, particularly liquids, such as gasolineand water. This must be accomplished from the air. In such cases, thetransporting plane delivers the goods by landing in the area or bydropping containers by parachute. Often there is no landing area, andthe supplies must be dropped by parachute.

Parachute droppings have several disadvantages. If there is any wind,the parachutes tend to blow and drift for mile. When they do land, theyare often hung up in trees and are difiicult to reach. Finally, it is avery expensive method of supply in that the parachutes themselves areexpensive and are seldom recovered and they occupy considerable space inthe plane delivering the goods and thereby reduce the net pay load ofsupplies in the plane.

The elastic bag of the present invention permits dropping of flowablematerial at high velocity from an airplane flying at high altitudes sothat the material may be dropped without substantial inaccuracy due towind forces. Such a method of delivery is unusual and very practicalsince it does not require parachutes or other heavy equipment to reducethe velocity during fall and does not require complicated or expensiveequipment. According to the present invention, a strong flexible elasticbag or container is provided having elastic top and bottom walls whichmay be stretched a substantial amount radially. This bag is filled withliquid or freely flowing fineparticles and while so filled is droppedfrom an airplane at a substantial altitude and allowed to fall at highvelocity. Means are provided for stabilizing the bag during its fall tocause the container to strike the ground with its axis upright, so thatthe elastic top and bottom walls of the container can absorb the impactwith the ground without bursting the container or losing its contents.The bag is stabilized while it falls at high velocity so that its axisremains upright during the fall. The stabilizing step is performed bymeans carried by the container which does not add materially to theWeight of the container.

The container may be shaped to provide the necessary stabilizing meansor may be provided also with auxiliary stabilizing means. A suitablestabilizing means may be provided by shaping the bottom wall of thecontainer so that it presents a convex surface when the container is,

filled and freely falling. Such a convex surface inherently tween thewings of an aircraft so as. to maintain the conhas the sameself-righting effect as the dihedral angle betainer in its uprightposition during its free fall. The vertical projection of any sidedropping below level increases as the projection of the opposite siderising above center decreases, resulting in a corresponding shift inwind pressure which in turn causes the container to right itself andequalize the wind pressure about the convex surface.

When the container is dropped as indicated above, it

Patented July 11, 1961 contents of the container can then be removedthrough a convenient plug or valve, or stored in the container untildesired for use.

An object of the present invention is to provide an article fordelivering supplies from air vehicles vto the ground receivers in freelyfalling containers.

A further object of the invention is to provide a container which isstabilized during fall so that its velocity is limited without the needfor heavy parachutes or the like and so that the container can absorb animpact with the ground at high velocity.

Another object of the invention is to provide a container which may bedropped at high velocity so that it will land at the desired location.

Another object of the present invention is to provide'a container whichis so shaped and constructed that it can be filled with liquid or thelike and dropped from great heights and land without bursting and withits contents intact.

A still further object of the invention is to provide containers whichyieldingly resist and absorb the large impact forces arising when suchcontainers strike the ground.

Other objects and advantages of the invention will become apaprent fromthe following detailed description and from the accompanying drawingsillustrating this invention, in which like numerals relate to like partsthroughout the several views.

FIGURE 1 is a front elevation, partially in cross section, of acontainer constructed in accordance with the present invention.

FIGURE 2 is a top plan view of a quarter of the container of FIG, 1;

FIGURE 3 is a front elevation, partially in cross sec tion, of thecontainer of FIG. 1, filled with liquid; i

FIGURE 4 is a cross-sectional detail of the middle juncture of thesubject container;

FIGURE 5 is an illustration of the change in shape taken by a loadedcontainer as its strikes the ground, the container being shown in solidlines to show its shape during free fall and at the first instant ofimpact, and in dotdash lines to show its shape as it stretches radiallyto absorb the im act;

FIGURE 6 is a front elevation, partially in cross section of a secondform of container constructed in accordance with the subject invention;

FIGURE 7 is a front elevation, partially in cross section, of thecontainer of FIG. 6 filled with liquid; and

FIGURE 8 is a detailed enlargement, in cross section, of the valve forthe container of FIG. 6.

In accordance with the present invention, a container is filled withflowable materials such as gasoline, water, dry powders, or freelyflowing fine particles, such as sugar, salt, flour, and the like, andthen dropped from an air'vehicle to the ground. Persons on the groundserving as receivers collect the containers and empty them. Any suitableair vehicle, such as .an airplane, helicopter, balloon, or dirigible maybe used. The containers may be filled either on the ground or in thevehicle. It is contemplated that this process may be used in bothmilitary and civilian work to supply persons in isolated positions. Itis also contemplated that containers may be dropped from air vehiclesonto the ocean or inland lakes.

The container of this invention is a relatively thinwalled hollow bodyand preferably has filling means'or a plug in the top portion, generallyin the center thereof. The container shape should be rounded and curvingand have no sharp corners or stress concentration points. Ex-

cellent results may be obtained where the container is 'a preferred typeof container is symmetrical about its vertical axis so as to have asubstantially uniform radial cross section throughout its circumference.The container can be molded in one piece or formed of two disc piecesintegrally joined at the edges or otherwise manufactured.

The container may be generally spheroidal or ellipsoidal and ispreferably oblate or depressed at the poles so that it has a diameterseveral times its axial height. Best re- 'sults are obtained where thecontainer, when in the filled condition and resting on a horizontalsupport has high oblateness and is generally in the form of an oblateellipsoid of revolution having a horizontal width or diameter that is atleast five times the axial height of the container, the convex bottomportion of the container preferably having less curvature than and ablunter profile than the convex top portion of the container.

The containers themselves are subject to extreme forces and areconstructed in accordance with definite limitations. In the first place,it is assumed that, in the great majority of drops, the containers willreach their maximum or terminal velocity as they fall to and beforereaching the ground. Thus they will normally strike the ground afterthey reach their terminal velocity. To minimize the impact forces,therefore, the container is designed to have a minimum terminal velocityand to have as much air resistance as can be incorporated thereinwithout being unduly complex, costly, heavy to transport, bulky orcumbersome. The containers are designed to have maximum free fallvelocities (terminal velocities) below 300 feetper second and preferablyaround 100 feet .per second or below. The container is shaped tofacilitate aiming and directing on a predetermined flight course and tominimize spinning and whirling in the air or other factors which wouldtend to cause the container to fall in an erratic fashion.

It will be understood that the term terminal velocity as used in thespecification and claims means the maximum velocity of the containerwhen it is allowed to fall freely from a height greater than thatnecessary to allow the container to reach such velocity. The terminalvelocity is, therefore, determined by the air resistance of thecontainer rather than the height from which it is dropped.

One form of container or bag constructed in accordance with the subjectinvention is illustrated in FIGS. 1 to 5. This bag 10 comprises acircular top sheet or disc 1 which interlocks with a circular bottomsheet or disc 2 at seam 3. As shown in FIG. 4, the edge 4 of sheet 2laps over the edge 5 of sheet 1 and they are vulcanized or cementedtogether to provide an integral construction. At the top of the bag is afilling means or check valve 6 with a 'cover 7, said valve beingconstructed so that the liquid in the container cannot escape. Asuitable construction is shown in US. patent application Serial No.244,382, filed August 30, 1951, by Clarence H. Nefi, now Patent No.2,677,388. The valve cover is tied to the bag by a string or lanyard 8.

The inner side of each sheet 1 and 2 should be resistant to aromaticliquids if used to transport gasoline or other chemicals. As hereinshown, the inner side of each sheet 1 and 2 has a thin layer 9 ofrubber-like material, such as Hycar, Thiokal, or the like, which isresistant to aromatic organic liquids so that gasoline can betransported therein without injury to the bag walls. The inner liningpreferably is more flexible than the bag walls proper so that the liningdoes not absorb shock forces or become separated from the walls.

The material used in making the container 10 should be tough, abrasionresistant and flexible. Suitable materials are natural and syntheticrubbers and other rubberlike materials. The required physicalcharacteristics of the material must be adapted to the goods transportedin the container taking into account their specific gravity, solventaction, compatibility, and sanitation requirements of the goods.

A suitable material must satisfy a combination of several requirementsin as even a balance as possible. The material has to be elastic andstretchable in order to give and distort on landing and thereby absorband dis sipate the landing forces. At the same time, its modulus ofelasticity should be suflicient so that the container, when filled,retains its shape on the ground and the walls do not collapse. Theelastic bag preferably should have suflicient rigidity in the filledstate so that it can be stacked readily and moved about. Preferably, itshould be shaped and of sufficient rigidity so that the filling means orplug 7 can be removed while the bag 10 is resting on the ground and sothat the contents of the bag will not be forced from the opening. Thematerial forming the bag 10 should also have a sufiicient modulus ofelasticity so that the shape of the container during free fall is oneproviding maximum air resistance and is not distorted to a streamline,teardrop shape. The material also should have toughness and abrasionresistance to stand handling and resist ground hazards, such as trees,rocks, and stubble. The walls of the container used in accordance withthe present invention should have no unstretchable, continuous,reinforcing material therein because this unduly limits the flexibilityand elongation of the bag.

The shape and construction of the container 10 and its elastic rubberwalls 1 and 2 will be apparent from the drawings. The container 10, whenfilled and resting on a fiat horizontal support as shown in FIG. 3,assumes substantially the shape of an oblate ellipsoid of revolutionsubstantially symmetrical about a vertical axis in which the top andbottom discs 1 and 2 are convex or bowed outwardly. If the discs 1 and 2are laid substantially flatwise against one another, the overlappingdisc 2 has a greater diameter than the other as is apparent from thedrawings.

The container may be stabilized during its free fall in different waysto cause the container to land with its axis upright. Such a stabilizingstep preferably is performed by lightweight means carried by thecontainer itself; for example, by shaping the bottom and marginalportions of the container in such a manner that the axis tends to remainupright during the fall.

The container 10 shown in FIGS. 1 to 5 and the equivalent container 12shown in FIGS. 6 to 8 of the drawings preferably are shaped to providemeans for stabilizing the filled container during its free fall. Suchstabilizing means minimizes the terminal velocity of the container,minimizes the landing shock and stresses on the container, and causesthe container to land in its normal upright position so as not to injurethe valve or plug for filling and emptying the container. Thestabilizing means will be further described as applied to the containerof FIGS. 1 to 5, it being understood that identical means may beemployed with the container 12, the claims appended hereto being drawnto cover both containers.

In order to stabilize the filled container 10, the bottom of thecontainer opposite the filling valve 6 and the portron near the maximumhorizontal diameter of the container is shaped so that said container,when filled and freely falling, provides increasing air resistance onone side as it is tilted earthward from the horizontal. The outerportions of the cross-sectional curve of the contamer preferably aremade to be fiat (straight), or concave, or only slightly convex when thecontainer is freely falling, for example as shown in FIG. 5, so thatwhen tilted from the horizontal, the air resistance of the upwardportion will decrease and the air resistance of the lower portion willincrease. This provides a self-righting effect similar to the dihedralangle in airplane wings. The shape of the stabilizing means at themargins of the filled container 10 is clearly shown in FIG. 4, and theconvex shape of the bottom wall 2 is clearly shown in FIG. 5. As hereinshown the profile (or radial vertical cross section) of the wall 2 ofthe container 10 ad- .jacent the maximum horizontal width or diameter(margin) when the container is in the filled condition approximates astraight line as will be apparent from FIGS. 4 and 5. The convex shapeof the bottom wall 2 of the container provides means for stabilizing thecontainer so that it remains in an upright position as it falls.

The action of the container or bag upon striking the ground isillustrated in FIG. 5. At position A, shown in solid lines, the filled.bag 10 is shown just touching the ground at the instant the bag firststrikes the ground, this also representing the shape of the bag as itappears during its free fall. As shown, this shape is substantiallylenticular, the filled oblate bag retaining its high ellipticity as itfalls. A few instants after initial impact with the ground, at positionB shown in dot-dash lines, the bag 10 has increased contact, and theliquid is beginning to spread out horizontally. A few instants later, atposition C shown in dot-dash lines, the bag 10 has flattened like apancake as the liquid moves outwardly in radial directions from thecenter of impact. Here the bag is severely tensioned as the energy ofthe liquid is absorbed. Prior to striking the ground, however, theenergy is converted into forces which may be resolved into vertical andhorizontal forces. The ground absorbs the vertical forces and the bagabsorbs horizontal forces. The elastic material forming the bag sidewalls therefore must be strong enough to absorb and dissipate thesehorizontal forces-that is, all the forces not absorbed by the ground.

7 The material for the container 10 can be any highabrasion-resistant,nervy, flexible rubber or rubber-like material, such as natural rubber,butadiene and isobutylene copolymers, polyvinyl alcohol, and otherelastomeric materials. The material should be compounded to provide highabrasion resistance and toughness. Minimum elongation at break should be400' percent. The bag wall section, regardless of thickness, ought topull 2000 p.s.i. or above at 500 percent elongation. In general, thethickness of the bag walls may be reduced as the modulus of the materialemployed to make the walls increases, and vice versa. A container havinga wall pull of 4000 psi. at 500 percent elongation would be suitable. Arubber stock preferably should have 25 parts or more of a reinforcingcarbon black or equivalent to provide toughness, hardness, abrasionresistance, and resistance to cutting. High quality tire tread stocksatisfying the above-noted physical characteristics is suitable for usein the containers of the present invention.

It is contemplated that bags constructed in accordance with the subjectinvention Will have a capacity of five, ten, twenty-five, or even moregallons. Using the same stock, the bag wall thickness should beincreased when the bag is used to drop heavy liquids, such as water,instead of lighter liquids, such as gasoline or the like.

To illustrate this invention, a container similar to the one disclosedin the drawings was made up of a high quality tread compound of fivegallon capacity. This compound had a modulus of elasticity of 4000p.s.i. at 500 percent elongation and a hardness of around 60 durometer.The wall thickness was 0.156 inch. Such a drum, filled with water, wasdropped from an airplane at an altitude of 2000 feet. The drum landeduninl'llled and was drained of the water. Computations showed that theterminal velocity should have been reached after approximately 750 feetof fall so that the container reached its terminal velocity beforestriking the ground and must have struck the ground at its terminalvelocity. Thus the container was subjected to no more severe conditionsif dropped from 3000, 4000, or 5000 ft. altitude.

It will be noted that the elastic top wall 1 radially outwardly of thevalve 6 and the elastic bottom wall 2 are free of inextensiblereinforcement even at the seam 3 so that the bag 10 can readily bestretched radially. However, since .the valve 6 prevents stretching ofthe central portion of the top wall, it is often preferable to prowideextra material in the top wall of the bag--.-to facilitate stretchingthereof. FIGURES '6, 7 and 8 show a modified form of container 12 whichmay be identical to that of FIGS. 1 to 5 except for the amount of rubberin the top wall. As shown in FIG. '6, the empty rubber bag 12, whencollapsed and resting on a flat horizontal support, has acircumferential hump portion 11 around the top portion of the bagadjacent the filler means due to the fact that the top wall of thecontainer has a greater external diameter than the bottom wall connectedthereto. The hump portion 11 provides extra stretchable material for thetop portion of the container so that it can stretch evenly with thebottom portion, or in other words, so that the top and bottom portionsof the container have approximately the same area of stretchablematerial. The fitting around the plug 13 is unstretchable and reducesthe-effective stretch of the top portion of this container. Thus anannular hump 11 can be provided to equalize this situation. When thecontainer 12 is filled, the hump 11 is preferably substantiallyeliminated as seen from FIG. 7.

The filling means for the container shown in FIGS. 6 to 8 may be thesame as in FIGS. '1 to 5; but, as herein shown, the filling meanscomprises a plug '13 which screws into the socket means 1-4 mounted inthe center of the top portion of the container. The plug and socketmeans are preferably of a molded, shock resistant polymeric plastic,such as a fiberglass-polyester composition. A washer 15 is insertedintermediate the plug and socket to prevent leakage.

It will be understood that the container 12 may be constructed so thatit will function substantially the same as the container 10 describedabove, even where extra material is provided in the top wall of the bag,the bottom and marginal portions of the container preferably beingshaped during free fall the same as in the container 10. The bottom wallof the container 12 is convex, when the container is filled and fallingfreely, so as to provide means for stabilizing the container to maintainthe axis of the container in an upright position.

It will be seen that the rubber container of the present invention ismade up of many elements which may be united or integrally joined. It isalso apparent that the elements making up the rubber container performseveral different functions. These elements provide means for enclosingthe liquid, means for holding the bag in an oblate shape and formaintaining a high ellipticity, and also means for providing high airresistance and for stabilizing the bag during its free fall. The termmeans is used in the specification and claims in the broad sense inaccordance with the patent laws and is not used in the limited sense tocover only those means which perform a plurality of functions and areshown specifically in the drawings.

It is to be understood that the invention disclosed can be carried outin a number of ways within the scope of the appended claims and that itis not to be limited to the specific embodiments which are hereindescribed for purposes of illustration. I

Having described my invention, I claim:

1. A container for aerial delivery of liquid to the ground from an airvehicle traveling at substantial altitude comprising an extensibleelastic rubber bag with a volumetric capacity of at least five gallonshaving means comprising thin marginally connected generally circular topand bottom walls which may be extended several times their normaldiameter, the rubber of said walls containing a reinforcing .carbonblack and being capable of withstanding a tension of at least 2000pounds per square inch when elongated 500 percent, the rubber marginalportion of said bag uniting the top and bottom walls being radiallystretchable and stretching with said top and bottom walls when the bagstrikes the ground, said bag when completely filled with said liquid andresting on a fiat horizontal surface having an axial height no greaterthan one-fifth the horizontal width of the container, filling means forthe bag forming a part of said bag, the marginal and bottom portions ofsaid bag maintaining the filled bag generally in the shape of an oblateellipsoid of revolution, said bottom wall providing substantial airresistance to reduce the terminal velocity of the bag during free fall,said marginal portion of said bag having a radially outwardly projectingportion of readily stretchable material forming part of the bag wallsand extending along the periphery of said bag at the junction of saidtop and bottom walls, and a liner of elastic rubber-like material thatis resistant to aromatic organic liquids, said liner fitting within thebag and being more readily extensible than said walls.

2. A free falling droppable container for aerial delivcry offree-flowing material to the ground from an air vehicle traveling atsubstantial altitude comprising an elastic rubber bag which may beextended radially several times its normal diameter, said bag comprisingmeans having a volumetric capacity of at least five gallons and havingthin marginally united top and bottom generally circular wall portionsof an elastic rubber material which withstands a tension'of at least2000 pounds per square inch when elongated 500 percent so that the bagmay be stretched radially to absorb landing forces, filling means nearthe center of said top wall whereby the bag may be filled and emptied,said top and bottom wall portions being free of inextensiblereinforcement radially outwardly of the filling means and free tostretch radially, the bag when filled with at least five gallons of aliquid hydrocarbon and resting on a flat horizontal surface having anaxial height no greater than one-fifth its diameter, the bottom wallbeing generally flat when the bag is empty and said bottom wall isunstressed and being convex when the bag is filled with liquid, theconvex bottom wall having a central portion that increases in curvaturefrom the center radially outwardly and a marginal portion that increasesin curvature from the margin of the bag radially inwardly to saidcentral portion, whereby the bottom wall assists in stabilizing thefreely falling bag and faces the ground throughout the fall of the bag,said bottom wall providing the bag with a large air resistance relativeto the weight of liquid and with a terminal velocity of notsubstantially more than 100 feet per second, and a liner of an elasticrubber that is resistant to aromatic organic liquids fitting against thewalls of the bag and enclosing the liquid therein.

3. A free-falling droppable container for aerial delivery of gasoline tothe ground from an air vehicle traveling at substantial altitudecomprising an elastic rubber bag which may be stretched radially severaltimes its normal diameter, said bag having generally circular top andbottom wall portions integrally joined by an annular marginal portionand having a volumetric capacity of at least ten gallons, said top,bottom and marginal portions comprising an elastic rubber material whichpulls at least 2000 pounds per square inch when elongated 500 percent toenable said portions to stretch radially and absorb impact forces whenthe bag strikes the ground in an upright positon, means near the centerof said top wall for filling and emptying of said bag, said bag beingfree of inextensible reinforcement radially outwardly of the fillingmeans, the wall portions and marginal portions of the bag causing thebag to have an oblate shape when the bag is filled with gasoline andfalling freely and to have a large air resistance limiting the terminalvelocity of the bag to not more than 100 feet per second, said bag whenfilled with gasoline and resting on a horizontal surface having an axialheight not more than one-fifth its diameter, the interior portion ofsaid bag enclosing and contacting the gasoline being formed of anelastic rubber-like material that is resistant to aromatic organicliquids.

4. A container as defined in claim 3, wherein said means for filling thebag consists of non-metallic polymeric material.

5. A free falling droppable container for aerial delivery of gasoline tothe ground from an air vehicle traveling at an altitude of severalthousand feet comprising an extensible elastic rubber bag with avolumetric capacity of at least five gallons having generally circulartop and bottom wall portions overlapped at the margins and integrallyjoined to provide a thickened annular marginal portion thatprojectsradially outwardly when the bag is filled with liquid, said top,bottom and marginal portions comprising an abrasion-resistant elasticrubber material containing a reinforcing carbon black and capable ofpulling 4000 pounds per square inch when elongated 500 percent to enablesaid top, bottom and marginal portions to stretch radially and absorbimpact forces when the bag strikes the ground at its terminal velocity,means near the center of said top wall for filling and emptying of saidbag, said bag when filled with liquid and resting on a fiat horizontalsurface having an axial height no greater than one-fifth the horizontaldiameter of the container, the wall and marginal portions of said bagmaintaining the filled bag in an oblate shape during its fall andlimiting the terminal velocity of the bag during free fall to no morethan feet per second, and a liner of elastic rubber-like material thatis resistant to aromatic organic liquids, said liner fitting within thebag and enclosing the liquid.

6. A free falling droppable container for aerial delivery of gasoline tothe ground from an air vehicle traveling at substantial altitudecomprising an elastic rubber bag which may be stretched radially severaltimes its normal diameter, said bag having generally circular top andbottom wall portions integrally joined by an annular marginal portionand having a volumetric capacity of at least 10 gallons, said top,bottom and marginal portions being formed of an abrasion-resistantcarbon-black-reinforced elastic rubber material which may be elongated500 percent and which is capable of withstanding a tension of 4000pounds per square inch to enable said portions to stretch radially andabsorb impact forces when the bag strikes the ground, means near thecenter of said top wall for filling and emptying of said bag, said bagbeing free of inextensible reinforcement radially outwardly of thefilling means, said bag when filled with gasoline and resting on a fiathorizontal surface having a high oblateness and an axial height nogreater than onefifth the horizontal width of the container, the walland marginal portions of the bag maintaining the high oblateness of thefilled bag during its free fall and providing substantial air resistanceto limit the terminal velocity of the bag during free fall to no morethan 100 feet per second, the interior portion of said bag enclosing andcontacting the gasoline being formed of an elastic rubberlike materialthat is resistant to aromatic organic liquids.

7. A container as defined in claim 6 wherein the marginal portion of thebag includes means for stabilizing the bag to maintain the axis thereofin an upright position during its fall.

8. A free falling droppable container for aerial delivery of gasoline tothe ground from an air vehicle traveling at substantial altitudecomprising two substantially flat circular sheets of toughabrasion-resistant elastic rubber joined at their margins to provide ahollow radially extensible bag with a capacity of at least five gallonshaving a thickened annular marginal portion, the rubber of said sheetsbeing reinforced with carbon black and being capable of withstanding atension of at least 2000 pounds per square inch when elongated 500percent, said marginal portion projecting radially outwardly and havingan outside diameter at least five times the axial height of the bag whensaid bag is filled with liquid and resting on a flat horizontal surface,shock-resistant polymeric filling means for the bag forming a part ofsaid bag, the wall and marginal portions of the bag maintaining thefilled bag in a generally lenticular shape and limiting the terminalvelocity during free fall to no'more 9 than 100 feet per second, thebottom wall of the filled bag being convex and having a downwardly bowedcross section decreasing in radius of curvature adjacent said marginalportion, and a liner of elastic rubber that is resistant to aromaticorganic liquids fitting within the bag and enclosing the liquid therein.

9. A free falling droppable container for aerial delivery of gasoline tothe ground from an air vehicle traveling at substantial altitudecomprising an extensible elastic rubber bag with a volumetric capacityof at least five gallons having thin marginally connected generallycircular top and bottom walls which may be extended several times theirnormal diameter, the rubber of said walls containing a reinforcingcarbon black and being capable of withstanding a tension of at least4000 pounds per square inch, the rubber marginal portion of said baguniting the top and bottom walls being radially stretchable andstretching with said top and bottom walls when the bag strikes theground, said bag when filled with gasoline and resting on a flathorizontal surface having an axial height no greater than one-fifth thehorizontal width of the container, filling means for the bag having anopening at the wall of the bag to permit filling of the bag and meansfor closing said opening, means including the wall and marginal portionsof said bag maintaining the filled bag in an oblate shape during itsfree fall and limiting the terminal velocity of the bag during free fallto no more than feet per second, and a liner of elastic rubberlikematerial that is resistant to aromatic organic liquids References Citedin the file of this patent UNITED STATES PATENTS 685,894 Williams Nov.5, 1901 1,166,862 Smoot Jan. 4, 1916 1,335,467 Traynor Mar. 30, 19201,340,236 Moeble May 18, 1920 1,834,978 Shapiro Dec. 8, 1931 2,209,570Kraft July 30, 1940 2,406,903 Rethorst Sept. 3, 1946 2,423,940 KruppJuly 15, 1947 2,430,905 Bradley Nov. 18, 1947 2,641,292 Quillinan June-9, 1953 2,724,418 Krupp Nov. 22, 1953 2,784,755 Bender Mar. 12, 1957OTHER REFERENCES Marks Handbook, third edition, page 760, published 1930by McGraw-Hill Book Co., NY. (Copy in Div.

